Numerous additives heretofore have been developed for use in the preparation of grease compositions capable of performing under high pressure, high temperature and high speed conditions. Various of these additives include lead-sulfur systems, heavy metal sulfide systems, particularly molybdenum disulfide systems, phosphate salt-oil soluble sulfur, chloride, or carbonate systems, phosphate salt-oil insoluble sulfur, chloride or carbonate systems, and organic phosphate systems, to mention a few. Exemplary of patents directed to such systems are U.S. Pat. Nos. 3,344,065, No. 4,107,058 and No. 4,305,831. While systems of the type mentioned provide some effectiveness under extreme temperature, pressure, and high speed conditions, they have a number of shortcomings, particularly from a material cost standpoint, and, equally importantly, from a toxicity and/or environmentally deleterious standpoint. Thus, by way of illustration, molybdenum disulfide which, perhaps, has been accorded the most general acceptance as an additive for the preparation of extreme pressure lubricants, is comparatively expensive and represents an unfavorable cost factor to manufacturers of such lubricants. Also, with systems employing molybdenum disulfide, or systems which incorporate sulfur compounds other than molybdenum disulfide, there is the possibility of breakdown of such compounds under severe and/or prolonged conditions of use, resulting in the release of sulfur. The sulfur, which may be in a free or combined state, can, in time, cause serious corrosion to metal parts in contact with the lubricant compositions, and, further, may exacerbate handling and disposal of spent lubricant.